Fuel-feeding apparatus



May 15, 1923. 1,454,979

J. E. MUHLFELD ET AL FUEL FEEDI NG APPARATUS Filed Nov. 21, 1918 Afro/mfr Ps .f3 May 15, 1923.

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Applitlon med november-91, 19m. l No. 2,459.

To all whom. t may concern.' K

Be .it hown that we, JOHN E. n l .l and VmoINrUs Z. Csmoms'rr, Nth citlze s of the United States of America, the former a resident of Scarsdale, in the county of Westchester and State of New York, and

the latter a resident of Bronxville, in the,

county of Westchester and State of New York, have invented certain new and useful 11i-Improvements in Fuel-Feeding Apparatus,

of which the following is a speclfication.

rlhe present invention relates to an improved process and apparatus for feeding and mixing ulverized fuel and air. Heretofore it has een the usual practice, in such apparatus to provide two parate sources of air of dierent velocit pressures, the one for providing mixed fue and air, while the other conveys the mixed fuel and air to the 2o mixi chamber of the furnace.

ln t e present invention we proposed to provide a single source of air having velocity pressure (blast air) and: in connection therewith a main conduit, a velocity increasing means, in the present embodiment a venturi structure, anda branch conduit extending from said main conduit and returning to the same and receiving fuel from the fuel feeder, which is mixed therewith before 30 the reentrance of said branch current into the main current. To this end lthe present invention contemplates the idea of settingP up at one point in a current of blast air, an increase in velocity, diverting a -branch.

' 85' current of air which passes through the feeder receiving fuel, said branch current returning to the current of blast air at the point of increased velocity. The eect of A the increase in velocity at this point is to t0 maintain a dow of air throu h the branch conduit, the velocity of whi is decreased by the handling of the pulverized fuel. Owi vto the dierence of velocity in the branc conduit and the point of increased e5 velocity, a feeding of the mixed fuel and air into the main current of air results.

With the above and other objects in view an apparatus is shown in the drawings by way of"examp1e for carrying out my invention and the invention will be hereinafter more fully described with reference thereto and finally pointed out in the appended claims.

ln the drawings: f Fig. 1 is a vertical sectionalview `of a form of apparatus, suitable for carrying out our inventionand y Fig. 2 is a horizontal section of the venturi structure.

Referring to the wi, a main con-v duit 'l0 is connected at one end to a blower for supplying blast air thereto, and at its other end extends into the re-box ofthe furnace. At a point intermediate its end a venturi structure is provided as at 11, the eect of this being to increase the 4velocity at this point.

From a point in the main conduit l0 ahead of (on the way to) the venturi structure, a

secondary branch conduit 12 extends from.

the conduit 10 to the pulverized fuel feeder 13. As shown, the branch conduit 12 is smaller than the main .conduit 10, so that i adequate air velocity may be maintained therein by the constriction of the main conduit at 11. The feeder 13 may be ofany suitable construction and in this example includes a screw conve or 13 below the fuel bin 13", which feeds uel into the current of air, a mixing paddle 13"'` being provided upon the shaft of the conveyor 1n the path of the current of air. The conduit 12 is extended at the outlet end of the feeder and returns to the conduit 10, terminating in a forwardly bent delivery jet nozzle 12a having its outlet disposed in the restricted oriice of the venturi structure.. The end of the nozzle may preferably be shiftable longitudinally to adjust its position relatively to the region of increased velocity in the restricted portion of the venturl. For this purpose we provide upon the nozzle a slidable sleeve 14 having a pair of lugs 14C and le and coted by links 15 to the cranks lever 16 mounted upon a transverse shaft 17 journaled in rings 18 and 19. At one end the shaft 17 has an operating handle 20, which upon being turned shifts' the sleeve 14 and thereby adjusts the end of the nozzle.

The opera-tion is as follows:

Blast air lows from the blower through the conduit 10 at a given velocity. Assuming this velocity to be the velocity of the air passing through the venturi is m plus the eect of the venturi, that is an increase in velocity at this point.- Beceusel of this di'erence in velocity at the pointof divergence of the current of air through the lconduit 12 and its point of. reentrance to the conduit at the venturi, a flow is set u through this conduit 12, into which the fue is fed and mixed from the feeder. The fuel thus mixed with air is ultimately ejected from the nozzle into the main current of air passing through the conduit 10, whereupon this mixed Vfuel and air is carried with the main current to the furnace. The velocity in the conduit at the outlet side of the feeder and the venturi is w velocit minus velocity utilized in the work of han ing the pulverized fuel for the venturi, of course, can only lcally increase the velocity in the main conuit. tube 12 by the effect of the ventu'ri causes ejection of the mixed fuel and air at a relatively great velocity. By regulating the nozzle through the handle 20 this may be accurately controlled.

Vith our invention the mixing of the fuel with air and the feeding of the fuel and air is carried out with a single source of` blast air, resulting in a compact, simple, and economical structure.

We have described a preferred embodiment of carrying out our invention and illustrated a suitable and preferred form of apparatus, but it is obvious that changes may be made therein within the spirit and scope thereof as defined in the appended claims, and that the invention is applicable lto the feeding of other substances than pulverized fuel.

We claim:

1. In fuel feeding apparatus, the combination of a mainl conduit for passage of blast air, with a venturi therein; a smaller secondary conduit branching from the main conduit at a point 0n the way to said venturi and returning to the main conduit at the throat of said venturi, and having there- The suction action created in the- Maaate said velocity increasing means and returning to the main conduit at said means, and having therein an air current of less velocit than the current in the main conduit; wit

a feeder in said secondary conduit for feedin fuel into the current therethrough for de ivery to and admixture with the main current, and means for varyin and regulating the positionof the secon ary conduit outlet into the main conduit in the region of increased velocity in said conduit.

3. ln fuel feeding apparatus, the combination of a main conduit for passage of blast air, with a venturi therein; a smaller secondary conduit branching from the main conduit at a point on the Way to said venturi and returning to the main conduit at the throat of said venturi, and having therein an air current of less velocity than the current in the main conduit; with a feeder in said secondary conduit for feedin fuel into the current therethrough, for de ivery to and admixture with the main current, and a delivery nozzle in the venturi throat discharging in the direction of the main air current and adjustable in the same direction.

ln testimony that they claim the foregoing as their invention, they have signed their names hereunder.

JOHN E. MUHLFELD. VIRGINIUS Z. LCACRISTI. 

